1. Field of the Invention
The present invention relates to a retaining and restraining structure for plural cell electrolyzers. More specifically, the present invention relates to a supporting structure including a plurality of longitudinal tension bar assemblies for retaining the cells of a plural cell electrolyzer in face-to-face orientation, and diagonal adjustable tie bars for restraining the electrolyzer cells in a vertical orientation.
2. Description of the Prior Art
The electrolysis of various fluid media is well known, and widespread. For example, the electrolysis of sodium chloride brine is by far the most important commercial process for producing chlorine and caustic soda, which electrolysis products are extensively employed in numerous other applications. Recently, there has been a tremendous interest in electrolysis cells incorporating permselective membranes which restrict gross hydraulic flow between compartments in such an electrolyzer. Because the membranes, typically cationic permselective membranes of a perfluorinated organic polymer matrix having ionogenic sulfonate groups attached thereto, preclude the flow of liquid while permitting, e.g., current-carrying sodium ions to pass, it is now possible to produce caustic soda of a predetermined concentration and nearly free from chlorides.
To obtain maximum utility from these cells incorporating permselective membranes, a multi-cell electrolyzer is conventionally employed. In this plural cell design, a number of semi-independent cells are arranged in serial fashion and provided with various means for permitting flow of the fluid medium to be electrolyzed, and means for electrical communication between and among the various cells comprising the electrolyzer. While such a design takes full advantage of the characteristics of the permselective membranes, precautions must be taken to prohibit fluid and/or gaseous leakage at, for example, points of mechanical connection of the cell components since, obviously, the advantage of the membrane characteristics would otherwise be lost. Thus, the art recognizes the need to provide reliable retaining and restraining structures to achieve a two-fold purpose. Broadly speaking, the individual cell frame members must be maintained in a fluid-tight intimate, face-to-face contact; and, the individual cells should be maintained in a substantially vertical plane.
To this end, there are various known retaining structures such as those exemplified in U.S. Pat. Nos. 3,875,040; 3,926,770; and 4,017,375. Typically, the support or restraining structures include a number of longitudinal tension bars or the like which are affixed to end frame members at the terminal ends of the electrolyzer. This arrangement allows for the exertion of a retaining compressive force on each of the cells comprising the electrolyzer. Vertical stability is achieved by rigid terminal frame members. Other arrangements suitable for these purposes are disclosed in U.S. Pat. Nos. 1,094,728; 1,535,185; and 2,881,123.
While generally efficacious for their intended purposes, the prior art support devices fail to fully account for ease of support and stability, and optimum serviceability. For example, in the event a cell or stage within the electrolyzer requires replacement, access is severely limited due to the large, rigid, and often cumbersome retaining and restraining devices based upon rail supports and hydraulically or mechanically actuated platens. Accordingly, the need exists to provide a support structure which insures all of the advantages of prior art assemblies, but which is materially simpler in design and which further allows ready access to the internal cells of an electrolyzer.